the upper limb of the human body, esp. the part extending from the shoulder to the wrist.

the upper limb from the shoulder to the elbow.

the forelimb of any vertebrate.

some part of an organism like or likened to an arm.

any armlike part or attachment, as the tone arm of a phonograph.

a covering for the arm, esp. a sleeve of a garment

the arm of a coat.

an administrative or operational branch of an organization

A special arm of the government will investigate.

Nautical . any of the curved or bent pieces of an anchor, terminating in the flukes.

an armrest.

an inlet or cove

an arm of the sea.

a combat branch of the military service, as the infantry, cavalry, or field artillery.

power; might; strength; authority

the long arm of the law.

Typography . either of the extensions to the right of the vertical line of a K or upward from the vertical stem of a Y. ?

an arm and a leg

a great deal of money

Our night on the town cost us an arm and a leg.

arm in arm

with arms linked together or intertwined

They walked along arm in arm.

at arm's length

not on familiar or friendly terms; at a distance

He's the kind of person you pity but want to keep at arm's length.

in the arms of Morpheus

asleep

After a strenuous day, he was soon in the arms of Morpheus.

on the arm

Slang . free of charge; gratis

an investigation of policemen who ate lunch on the arm.

put the arm on

Slang .

to solicit or borrow money from

She put the arm on me for a generous contribution.

to use force or violence on; use strong-arm tactics on

If they don't cooperate, put the arm on them.

twist someone's arm

to use force or coercion on someone.

with open arms

cordially; with warm hospitality

a country that receives immigrants with open arms.